DME 150 -> 179/chipping - Experts, please look

[Stefan Borch]

Hi guys

I tried asking these questions on Roadfly.org, but no one could help. Are the real experts in here?

My M30 runs the 150 DME and I would like to add a performance chip, but they are hard to come by for this build. I did try a US chip, but it had no effect on my European car...

I have found a lot of postings from people considering the swap, but I was unable to find anything about the results of the swap, except a quick report on improved idle.

Specs:
E32 735iA (yes, I know this is an E34 board, but I do believe it is of no importance in this case)
Build date 10/1986
NO O2 sensor or catalyst! Meaning 220bhp and 9.2:1 compression ratio vs. 9.0:1 standard (or so I have read)
1267355344 chip in 150 DME

1. Does anyone KNOW what will happen, if I upgrade my 150 to a 179? Will the ignition timing and/or the fuel mixture be all wrong? Or will something else go askew?

2. Will the higher compression make a difference on the ignition timing and so on, thus creating problems with a changed DME even without the chipping?

3. The other way around: Will the higher compression ratio make a difference on the ignition timing and so on, thus creating problems with a changed CHIP in the original DME?

4. Does anyone KNOW why the US performance chips has little or no effect on European cars, even though they are replacing the identically numbered chip in the same DME version?


Regards,
Stefan

[MarkD]

Hi guys

I tried asking these questions on Roadfly.org, but no one could help. Are the real experts in here?

I think there are a few...

My M30 runs the 150 DME and I would like to add a performance chip, but they are hard to come by for this build. I did try a US chip, but it had no effect on my European car...

I have found a lot of postings from people considering the swap, but I was unable to find anything about the results of the swap, except a quick report on improved idle.

Specs:
E32 735iA (yes, I know this is an E34 board, but I do believe it is of no importance in this case)
Build date 10/1986
NO O2 sensor or catalyst! Meaning 220bhp and 9.2:1 compression ratio vs. 9.0:1 standard (or so I have read)
1267355344 chip in 150 DME

1. Does anyone KNOW what will happen, if I upgrade my 150 to a 179? Will the ignition timing and/or the fuel mixture be all wrong? Or will something else go askew?

I have not compared the sensors used by those DME's but if it uses the same air flow meter part number, coolant temp sensor and flywheel sensors are in the same position, it's worth a try.

2. Will the higher compression make a difference on the ignition timing and so on, thus creating problems with a changed DME even without the chipping?

The small change from 9.0:1 to 9.2:1 should not be a problem.

3. The other way around: Will the higher compression ratio make a difference on the ignition timing and so on, thus creating problems with a changed CHIP in the original DME?

Probably not.

4. Does anyone KNOW why the US performance chips has little or no effect on European cars, even though they are replacing the identically numbered chip in the same DME version?


Regards,
Stefan

Because in that old DME, the chip has 3 or 4 maps for leaded and unleaded fuel. The map in use is selected by a coding plug. The chip you bought for a US spec car would only have the map for premium unleaded (with cat) modified, while your car is using the maps for leaded and no O2 sensor.

Mark

[Stefan]

Thanks for your reply, Mark. Very interesting stuff about the different maps stored in the chip. It brings up a few new questions:

1. Both the instrument cluster and the coding plug has been changed by a former owner. Any way to make sure the new coding plug is selecting the right map, or will any error reveal itself by a poorly running engine?

2. What happens if the map the coding plug selects is not available?

3. If tuning chips are made with only a single map, then how (and where?) can I get a matching chip? Has one even been made for my specific engine type? Most sellers only look at the DME number and doesn't care about the chip itself.

4. I wonder why my fuel tank filler opening is the small one, used for unleaded gas, if my car is supposed to run on leaded? Or is it just older cars using the same DME, like the 635i, that requires leaded?

Stefan

[Stefan]

Anyone?

[MarkD]

Thanks for your reply, Mark. Very interesting stuff about the different maps stored in the chip. It brings up a few new questions:

1. Both the instrument cluster and the coding plug has been changed by a former owner. Any way to make sure the new coding plug is selecting the right map, or will any error reveal itself by a poorly running engine?

I think you would need a dealer tp read the coding plug and check what map it is selecting.

2. What happens if the map the coding plug selects is not available?

There is always a map available, as it is selecting between 3 or 4 maps that are in every chip of that vintage. All that would happen is that lets say the plug is selecting map 2 and the tuner adjusted map 3, there will be no difference in performance detected.

3. If tuning chips are made with only a single map, then how (and where?) can I get a matching chip? Has one even been made for my specific engine type? Most sellers only look at the DME number and doesn't care about the chip itself.

I'd be willing to send you a chip to evaluate, and if it does not make a difference I'll adjust another map.

4. I wonder why my fuel tank filler opening is the small one, used for unleaded gas, if my car is supposed to run on leaded? Or is it just older cars using the same DME, like the 635i, that requires leaded?

Stefan

Possibly your car is made to run on unleaded but I am not familiar with any map for unleaded and no cat. I can send you a chip to try now or I can adjust the other maps and then send a chip but it would take some time before I can do that.

Mark

[Stefan]

Mark,
Thanks for the info. I have taken a notepad copy of your replies and saved the file in my 'E32' folder.

Thanks for the offer(s) too. Right now I am awaiting a chip, that one of the suppliers of chips for testing on my site will be providing (http://www.homeofsbc.com/Chip_Tuning..._tuning_1.html).

I am doing a lot of things to my car these days, so money is an object. But if this chip doesn't work either, I will try yours. Since you have one of the best names in the BMW chip tuning business, maybe I should do that anyway...

Stefan

P.S. I am very sorry about being anonymous here. I have registered, but I am not allowed to post when I am logged in! I have written the admin more than a week ago, but still no reply...

Contact: bmw@NOSPAMhomeofsbc.com